JP2007154785A - Cold trap and vacuum exhaust - Google Patents

Abstract

A cold trap that realizes low power consumption by realizing both an increase in adsorption capacity and high-speed exhaust, and a vacuum exhaust apparatus that uses a turbo molecular pump in combination with a cold trap having such advantages.
A cold panel (200) installed in an inner space of a vacuum chamber (20) and a cooling end (105) in the inner space of the vacuum chamber (20) are thermally connected to the cold panel (200) via a flexible heat conducting member (109). It was set as the cold trap 10 provided with the refrigerator 100 arrange | positioned. Moreover, it was set as the vacuum exhaust apparatus which connected the turbo-molecular pump via the piping in the vacuum chamber 20 in which such a cold trap 10 was installed.
[Selection] Figure 2

Description

  The present invention relates to a cold trap and an evacuation apparatus using the cold trap and a turbo molecular pump in combination.

  A conventional cold trap and vacuum evacuation apparatus will be described with reference to the drawings. 5 and 6 are explanatory views of a conventional vacuum exhaust apparatus. A vacuum exhaust apparatus 1 shown in FIG. 5 includes a vacuum chamber 2, a pipe 3, a cold trap 4, and a turbo molecular pump 5. In the vacuum chamber 2, various internal devices (for example, a sputtering apparatus, a food drying apparatus, etc.) 2a used under vacuum are arranged. In FIG. 5, the installation posture of the cold trap 4 and the turbo molecular pump 5 is limited to the vertical installation type, and the cold trap 4 and the turbo molecular pump 5 are arranged from the top.

The turbo molecular pump 5 exhausts the inside of the vacuum chamber 2. The turbo molecular pump 5 has different exhaust performance depending on the molecular weight (molecular size) of gas molecules to be discharged. In particular, it is difficult to exhaust water vapor having a small molecular weight. For example, when the gas in the vacuum chamber 2 is exhausted to about 10 ⁻⁶ Pa to 10 ⁻¹² Pa by the turbo molecular pump 5, Most of the residual gas is water vapor. If such water vapor remains in the vacuum chamber 2, the degree of vacuum and the vacuum environment are adversely affected.

Therefore, a cold trap 4 is provided upstream of the turbo molecular pump 5 (generally between the vacuum chamber 2 and the turbo molecular pump 5 as shown in FIG. 5).
The cold trap 4 allows gas to pass through in contact with a surface cooled to a very low temperature (hereinafter referred to as a cold panel), cools water vapor contained in the passing gas, and freezes it on ice to collect it. In this way, a vacuum environment with less water vapor can be obtained in the vacuum chamber 2.
By removing the water vapor from the cold trap 4, the gas from which the water vapor has been removed in advance is introduced into the turbo molecular pump 5, thereby improving the exhaust speed of the vacuum chamber 2 and lowering the ultimate pressure. In addition, the cold trap 4 can also freeze and collect other gases (for example, Br ₂ , NH ₃ , Cl ₂ , CO _2, etc.) by appropriately setting the cooling temperature. The vacuum exhaust apparatus 1 is such.

  In recent years, cold traps and turbo molecular pumps that can be installed in a horizontal orientation have also been commercialized, and there is a vacuum exhaust apparatus 1 'as shown in FIG. The evacuation apparatus 1 'includes a vacuum chamber 2', a pipe 3 ', a cold trap 4', and a turbo molecular pump 5 '. In FIG. 6, the vacuum chamber 2 ′ cold trap 4 ′ and turbo molecular pump 5 ′ are arranged side by side in the horizontal direction.

As another conventional technique, for example, the invention described in Patent Document 1 (turbo molecular pump) or Patent Document 2 (cold trap and vacuum exhaust device) is known.
Patent Document 1 describes a cold trap that is cooled by liquid nitrogen, and Patent Document 2 describes a cold trap that uses a GM (Gifford-McMahon) helium refrigerator.
These are all examples in which the installation posture is vertical.

JP-A-9-317688 (paragraph numbers 0022 to 0036, FIGS. 1 to 4) JP-A-11-294330 (paragraph numbers 0032 to 0049, FIGS. 1 to 3)

The conventional vacuum exhaust devices 1 and 1 'have the following problems.
(1) Since the water vapor exhaust rate and adsorption amount in the molecular flow region increase in proportion to the surface area of the cold panel, it is desirable to increase the surface area. However, if the surface area is simply increased, there is a problem that the movement of the gas passing through the cold panel is hindered and the exhaust resistance (exhaust conductance) increases.
(2) In order to increase the surface area of the cold panel, there are restrictions due to the pipe diameter and pipe cross-sectional area of the tubular casing in which the cold panel is accommodated. In general, the pipe diameter of the casing and the pipe diameter of the pipe 3 are equal, and the increase in the surface area of the cold panel is limited to the pipe diameter of the casing (that is, the pipe diameter of the pipe 3). It was.
(3) Since the cold trap is a reservoir-type exhaust device, maintenance such as regeneration processing and cleaning is necessary after a predetermined time has elapsed, but there is a problem that it is troublesome to remove from the pipe 3.

  Accordingly, an object of the present invention made in view of the above-described problems is to provide a cold trap that realizes low power consumption by realizing both an increase in adsorption capacity and high-speed exhaust, and a cold trap having such advantages. Another object of the present invention is to provide an evacuation apparatus using a turbo molecular pump together.

In order to solve the above problems, the cold trap of the invention according to claim 1 of the present invention provides:
A refrigerator having a compressor, an expander and a cooling end;
A flexible heat conducting member thermally connected to the cooling end;
A cold panel thermally connected to the flexible heat conducting member;
A high thermal resistance stay that is formed of a member having high thermal resistance and supports the cold panel;
A refrigerator in which a refrigerator is disposed on one surface, and a high heat resistance stay, an expander, a cooling end, a flexible heat conducting member, and a cold panel are disposed on the other surface;
A vacuum chamber having an opening;
With
The cold panel is arranged in the internal space of the vacuum chamber by closing the opening with a flange.

According to this configuration, the flexible heat conduction member interposed between the cooling end and the cold panel can connect the cooling end and the cold panel with almost no mechanical force. Adjustment work such as alignment when connected to the cold panel can be reduced.
In addition, even if the cold panel is deformed due to thermal expansion and contraction, the flexible heat conducting member absorbs the deformation, so that no extra load is applied to the cooling end of the expander. A large cold panel can be installed according to the conditions.
Further, since the flexible heat conducting member has a low thermal resistance, the cold at the cooling end is surely conducted to the cold panel to lower the temperature of the cold panel.
Further, by arranging the cold trap cold panel directly in the vacuum chamber in which a large space can be taken, the surface area of the cold trap surface for freezing and collecting water molecules can be increased, and the adsorption capacity can be increased.
In addition, there is no obstacle in the pipe to prevent the gas flow, and the exhaust conductance can be reduced.
In addition, since it is supported by a plurality of high heat resistance stays, the weight of the cold panel can be shared and the surface area can be increased by further increasing the size of the cold panel. In addition, since the high thermal resistance stay is difficult to conduct heat, the cold of the cold panel is hardly transmitted to the vacuum chamber, thereby preventing an increase in heat capacity.
By realizing both an increase in adsorption capacity and a reduction in exhaust conductance, the power consumption can be reduced synergistically.

The cold trap of the invention according to claim 2 of the present invention is
The cold trap according to claim 1, wherein
The high thermal resistance stay is
A titanium alloy pipe having a hollow portion and a through hole communicating with the hollow portion;
A fixing portion fixed to both sides of the titanium alloy pipe and attached to the flange and the cold panel;
It is characterized by providing.

According to this configuration, the high thermal resistance stay makes it difficult for heat to be transmitted from the cold panel, so the heat capacity of the cold panel is reduced.
In addition, the high thermal resistance stay, which is a hollow cylinder, has high strength, and the strength of the high thermal resistance stay can be increased according to the size and weight of the cold panel, so the load on the expander of the refrigerator is minimized. Can do.
In addition, since heat intrusion and vibration intrusion from the vacuum chamber or the flange portion can be minimized, a cold trap that is resistant to disturbances such as vibration and shock can be supplied.
In addition, even if there is a pressure change in the vacuum chamber, the same pressure is applied inside and outside the high heat resistance stay due to the through hole, so that a situation where mechanical distortion occurs in the high heat resistance stay regardless of the pressure change is avoided.

The cold trap of the invention according to claim 3 of the present invention is
In the cold trap according to claim 1 or 2,
The flexible heat conducting member is an oxygen-free copper mesh wire.

Since the heat resistance is the lowest as the flexible heat conducting member, the cold at the cooling end is reliably conducted to the cold panel, and the cold panel is cooled.
Further, since the temperature difference between the cooling end of the refrigerator and the cold panel can be reduced, the power consumption of the refrigerator is not increased.

The cold trap of the invention according to claim 4 of the present invention is
In the cold trap as described in any one of Claims 1-3,
A thermal insulation collar that mechanically connects the high thermal resistance stay and the cold panel and suppresses heat conduction;
It is characterized by providing.

  In addition, since the heat insulation collar makes it difficult for heat to be transferred from the cold panel to the thermal resistance stay, the heat capacity of the cold panel is also reduced in this respect.

The cold trap of the invention according to claim 5 of the present invention is
In the cold trap as described in any one of Claims 1-4,
The cold panel includes a flat panel made of a flat plate and a hat-shaped panel having a convex portion, and is formed by attaching a hat-shaped panel while contacting the convex portion with the planar panel.

  According to this configuration, since the cold panel has two panels, the surface area of the trap surface can be increased while keeping the diameter of the cold panel as it is, and the adsorption capacity can be increased. The hat-type panel is in direct contact, and the convex portion of the hat-type panel is in contact with the flat panel near the cooling edge, so that cold is efficiently transmitted and the thermal resistance is low.

A cold trap according to claim 6 of the present invention is
In the cold trap as described in any one of Claims 1-5,
The expander is a pulse tube expander.

  According to this configuration, the expander of the pulse tube refrigerator (hereinafter simply referred to as the pulse tube expander) does not have a movable part such as a non-metallic sliding material like the GM refrigerator, and is all made of metal. Therefore, the heating temperature during the regeneration process can be set to be significantly higher than that of the GM refrigerator having a movable part, and the reliability against heat shock can be improved. Further, the excitation force applied to the vacuum chamber can be reduced, and it can also be used in a vacuum chamber incorporating precision equipment such as an optical system.

A cold trap according to claim 7 of the present invention is
In the cold trap as described in any one of Claims 1-6,
The cold panel is made of pure titanium having a high thermal conductivity in a low temperature region.

  According to this configuration, since the surface temperature distribution of the cold panel can be made uniform as compared with a commonly used stainless steel material, the effective surface area of the cold panel can be increased.

A cold trap according to claim 8 of the present invention is
In the cold trap as described in any one of Claims 1-6,
The cold panel is made of copper or a copper alloy having a high thermal conductivity in a low temperature region.

  According to this configuration, the surface temperature distribution of the entire cold panel can be made uniform as compared with a commonly used stainless steel like pure titanium, so that the effective surface area of the cold panel can be increased.

A cold trap according to claim 9 of the present invention is
The cold trap according to claim 8,
The cold panel is characterized in that a protective layer for improving corrosion resistance is formed on the surface thereof.

  According to this structure, corrosion of the surface of copper or a copper alloy can be prevented by forming a protective layer that prevents gas from coming into contact with copper or a copper alloy.

A cold trap according to claim 10 of the present invention is
In the cold trap according to any one of claims 1 to 9,
A heating means connected to a current line via a current introduction terminal provided on the flange and heating the cold panel;
A temperature measuring means for measuring the temperature of the cold panel, connected to the signal line via a signal derivation terminal provided on the flange;
A heating means via a current line, a refrigerator via a control line, a temperature measurement means via a signal line, and a temperature control means connected respectively.
With
The temperature control means controls the refrigerator or the heating means so that the temperature of the cold panel is a predetermined temperature based on the temperature of the cold panel measured by the temperature measurement means.

According to this configuration, the temperature of the cold panel can be optimally selected by selecting an effective temperature according to the gas adsorption characteristics during adsorption, and effective in releasing moisture during the regeneration process. The temperature can be selected and controlled so that the temperature of the trap surface of the cold panel is optimized, and the surface temperature of the cold panel (trap surface) can be set to an arbitrary temperature optimum for adsorption / regeneration.
Further, the refrigerator, the heating means, and the temperature measuring means are integrally attached in a state where they are connected to each other inside and outside through a flange, so that they can be easily removed during assembly and maintenance.

A cold trap according to claim 11 of the present invention is
The cold trap of claim 10,
The heating means is arranged so as to be built in the cooling end,
The temperature measuring means is arranged so as to be built in or in contact with the cooling end.

According to this configuration, the temperature at the cooling end can be accurately controlled, and the cold panel can be heated uniformly and quickly, so that the temperature heating / cooling rate is increased and the measurement accuracy is improved. The temperature can be set to an optimum temperature for adsorption / regeneration.
In particular, by incorporating a heating means, outgas from a component such as a heater is not released into the vacuum chamber.

A cold trap according to claim 12 of the present invention is
The vacuum chamber includes an opening formed by an opening area through which at least a high thermal resistance stay, an expander, and a cooling end pass,
After passing the high thermal resistance stay, the expander and the cooling end through the opening of the vacuum chamber and closing the opening with a flange, the cooling end and the cold panel are thermally connected by a flexible heat conducting member, and the high thermal resistance stay And the cold panel are connected to each other so that the cold panel is disposed in the interior space of the vacuum chamber and is formed integrally with the vacuum chamber.

  According to this configuration, in addition to the above-described operation, the refrigerator, the expander, and the cooling end fixed to the flange pass through the opening. Therefore, it is only necessary to attach and remove the cold panel in a wide vacuum chamber. As a result, assembly and maintenance become easier.

A cold trap according to claim 13 of the present invention is
In the cold trap as described in any one of Claims 1-11,
The vacuum chamber includes an opening formed in the vacuum chamber with an opening area through which at least a high thermal resistance stay, an expander, a cooling end, a flexible heat conducting member, and a cold panel pass,
A refrigerator is arranged on one side, and the opening is closed by a flange on which the high thermal resistance stay, expander, cooling end, flexible heat conducting member and cold panel are arranged on the other side. A cold panel is formed in the internal space of the vacuum chamber by passing a high thermal resistance stay, an expander, a cooling end, a flexible heat conducting member and a cold panel through the opening of the vacuum chamber and closing the opening with a flange. Are arranged and formed integrally with the vacuum chamber.

  According to this configuration, in addition to the above-described operation, the cold panel passes through the opening of the vacuum chamber, so that assembly and maintenance are further facilitated.

An evacuation apparatus according to claim 14 of the present invention includes:
The cold trap according to any one of claims 1 to 13,
A turbo molecular pump that exhausts gas in a vacuum chamber formed integrally with the cold trap;
It is characterized by providing.

  According to this configuration, the cold panel has a cold panel with an increased surface area of the trap surface to increase the adsorption capacity for freezing and collecting water molecules. A low-pressure evacuation apparatus can be provided.

  According to the present invention as described above, a cold trap that realizes low power consumption by realizing both an increase in adsorption capacity and high-speed exhaust, and a turbo molecular pump in combination with a cold trap having such advantages. An evacuation apparatus can be provided.

  Next, the best mode for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an evacuation apparatus including a cold trap according to the present embodiment. FIG. 2 is a configuration diagram of the cold trap.

  As shown in FIG. 1, the vacuum exhaust apparatus 1000 of this embodiment includes a cold trap 10, a vacuum chamber 20, and a turbo molecular pump 30. The cold trap 10 roughly includes a refrigerator 100 and a cold panel 200. The refrigerator 100 supplies cold to the cold panel 200, but is characterized in that at least the cold panel 200 is necessarily arranged in the vacuum chamber 20.

The vacuum chamber 20 is, for example, a large box shape, and an internal device 21 (for example, a sputtering apparatus, a food drying apparatus, etc.) is disposed in the vacuum chamber 20. In this embodiment, the vacuum chamber 20 and the turbo molecular pump 30 are connected via the pipe 40. However, the turbo molecular pump 30 may be directly connected to the vacuum chamber 20.
The turbo molecular pump 40 is a well-known technology, but is a pump that alternately arranges a large number of moving blades and a large number of fixed blades, rotates the moving blades at an extremely high speed of tens of thousands of rpm, moves the molecules, and exhausts them. is there. There is an advantage that a clean vacuum can be obtained.
These cold trap 10 and turbo molecular pump 20 constitute an evacuation apparatus 1000.

Next, the configuration of the cold trap 10 will be described. The cold trap 10 is roughly divided into a refrigerator 100 and a cold panel 200 as shown in FIG.
The refrigerator 100 includes a compressor 101, a radiator 102, a flange 103, an expander 104, a cooling end 105, a heater 106, a temperature sensor 107, a heat conduction member 108, a flexible heat conduction member 109, a heat conduction member 110, and a seal. 111, a current introduction terminal 112, a signal derivation terminal 113, a controller 114, and a power source 115.
The cold panel 200 includes a flat circular panel 201 and a hat-shaped panel 202, and is circular although not shown. The cold panel 200 is connected to the flange 103 at a plurality of locations by a high thermal resistance stay 203 and a thermal insulation collar 204. Although not shown in the drawing, a plurality of high thermal resistance stays 203 (for example, four) are arranged on a circle having the cooling end 105 as a central axis, and are firmly fixed.

  The refrigerator 100 is specifically a pulse tube refrigerator, and includes a compressor 101, a radiator 102, an expander 104, and a cooling end 105. The refrigerator 100 is a closed type refrigerator using helium gas as a refrigerant, and is configured such that the cooling end 105 is cooled by the Stirling cycle of the expander 104 and the compressor 101. In an ordinary Stirling type refrigerator, the expander is mechanically composed of a piston and a cylinder, but in a pulse tube refrigerator, there is no moving part, and the gas (gas piston) in the pulse tube (not shown) plays a role. Is responsible.

A heat conducting member 108 is fixed to the cooling end 105 with a screw or the like. The heat conducting member 108 is connected to a flexible heat conducting member 109 that is deformable and has an inverted U-shaped linear body shape in FIG. Specifically, the flexible heat conducting member 109 is a braided net of oxygen-free copper, and is thermally coupled without applying a load to both due to its flexibility. A heat conduction member 110 is connected to the other side of the flexible heat conduction member 109.
The cooling end 105, the heat conduction member 108, the flexible heat conduction member 109, and the heat conduction member 110 are all formed of a member having a low thermal resistance. It reaches the heat conducting member 110 through the flexible heat conducting member 109.
In this embodiment, the number of the flexible heat conducting members 109 is one as is apparent from FIG. 2, but a plurality of the members may be connected. Further, although the heat conducting members 108 and 110 are interposed, the flexible heat conducting member 109 may be directly connected to the cooling end 105 or the cold panel 200. It is sufficient that the flexible heat conducting member 109 is thermally connected to at least the cooling end 105 or the cold panel 200.

  In the cold panel 200, as shown in FIG. 2, the flat panel 201 is in direct contact with the heat conducting member 110, and the convex portion of the hat-type panel 202 (boss having substantially the same diameter as the heat conducting member 110) is in heat conduction. A structure in which the heat conducting member 110, the flat panel 201, and the hat type panel 202 are integrally fastened with fixing bolts in a state where the flat panel 201 is in contact with the member 110 is employed.

  The cold panel 200 thermally connected to the heat conducting member 110 of the refrigerator 100 includes a cooling end 105, a heat conducting member 108, a flexible heat conducting member 109, a heat conducting member 110, a flat circular panel 201, and a hat-shaped panel. The cold is efficiently conducted to the entire cold panel 200 through the route 202. Further, since the cold panel 200 has two panels, the surface area of the trap surface is made larger than that of a single panel having the same circular diameter to increase the adsorption capacity.

  In this embodiment, an example in which two cold panels are attached is described, but it is possible to stack three or more. In this case, a plurality of hat-shaped panels are prepared, and the shape of each convex portion is narrowed down. A suitable outer diameter is obtained by processing or the like, and a plurality of hat-shaped panels are directly attached to the cooling end and stacked. By appropriately adjusting the outer diameter size and height of the convex portions, the cold panels can be formed by superimposing the hat-shaped panels on the cooling end portions.

The cold panel 200 has a large diameter and a large surface area. In order to support such a cold panel 200 with sufficient mechanical strength, a high thermal resistance stay 203 and a thermal insulation collar 204 are provided. In particular, the high thermal resistance stay 203 includes a titanium alloy pipe 203a, a through hole 203b, a threaded portion 203c, and a threaded portion 203d as shown in the structural diagram of the high thermal resistance stay in FIG. The screw portion 203c and the screw portion 203d are specific examples of the fixing portion, and other attachment methods can be employed.
The high thermal resistance stay 203 employs a configuration in which a through hole 203b is opened on a side surface of a titanium alloy pipe 203a. Since the titanium alloy has a large thermal resistance in a low temperature range, consideration is given to preventing cold from reaching the cold panel 200. Furthermore, since the heat insulation collar 204 is interposed when the high heat resistance stay 203 is attached to the cold panel 200, it is considered that the cold does not reach from the cold panel 200 also in this respect.

A high heat resistance stay 203 is attached to a flange 103 formed in the refrigerator 100 and covering the opening of the vacuum chamber, and the heat insulation collar 204 is sufficient to mechanically connect the high heat resistance stay 203 and the cold panel 200. Strength is secured. With such a configuration, even if ice adheres to the cold panel 200 and the weight increases, the high heat resistance stay 203 and the heat insulation collar 204 receive all the forces and are not mechanically deformed. A situation in which an unnecessary force is applied to 100 is avoided. In addition, a situation in which unnecessary force is applied to the cooling end 105 by the flexible heat conducting member 109 is avoided.
Further, both the high thermal resistance stay 203 and the thermal insulation collar 204 are formed of members having high thermal resistance, and both the heat conduction from the cold panel 200 to the thermal insulation collar 204 and the heat conduction from the thermal insulation collar 204 to the thermal resistance stay 203 are suppressed. Therefore, consideration is given so that cold is not conducted to the flange 103 in reverse. In this embodiment, the cold panel 200 can be further increased in size, and the collection ability can be increased. In addition, it can receive the cold weight of the cold panel 200. In addition, even if thermal expansion or contraction occurs, a cold trap that is resistant to disturbances such as vibration and shock is supplied so that no force is applied to the cooling end. it can. Also, unnecessary heat transfer between the vacuum chamber and the cooling end can be minimized.

A flange 103 is mechanically attached to the refrigerator 100. The compressor 101 is arranged outside the flange 103, and the expander 104 and the cooling end 105 are attached inside the flange 103. The flange 103 is wider than the opening area of the opening 22 of the vacuum chamber 20 and is formed to cover the opening 22.
Further, the expander 104 and the cooling end 105 pass through the opening 22 but cannot pass through the cold panel 200. Therefore, when mounting, the cold panel 200 is inserted while being removed, and the flange 103 is screwed into the wall surface of the vacuum chamber 20. After stopping, the cooling end 105 and the cold panel 200 are thermally connected in the vacuum chamber 20 by the heat conducting member 108, the flexible heat conducting member 109, and the heat conducting member 110, and further, the high heat resistance stay 203 and the cold panel 200 are cold-connected. The cold panel 200 is disposed in the vacuum chamber 20 by being connected to the panel 200.

The cold panel 200 is manufactured using pure titanium having a thermal conductivity higher than that of stainless steel at an extremely low temperature of about 70K (−203 ° C.). By using the cold panel 200 made of pure titanium, the surface temperature distribution can be made uniform as compared with a commonly used stainless steel material, and the effective surface area of the cold panel 200 can be increased.
Pure titanium also has the advantage of high corrosion resistance because it does not rust against water vapor or gas.

  The cold panel 200 may be made of copper or a copper alloy having a higher thermal conductivity than stainless steel in an extremely low temperature range of about 70K (−203 ° C.). Since the heat conductivity is thus large, the heat of the cooling end 105 is immediately conducted to the entire cold panel 200, and the entire cold panel 200 becomes the same temperature as the cooling end 105 in a short time. In this case, since the surface temperature distribution of the entire cold panel 200 becomes uniform and does not become a non-uniform temperature distribution unlike a stainless material usually used with a small thermal conductivity, the effective surface area of the cold panel 200 can be increased. The water molecules can be collected on the entire surface of the cold panel 200.

  Further, the cold panel 200 made of copper or a copper alloy is formed with a protective layer (specifically, a nickel plating layer) for improving corrosion resistance on the surface thereof so that the gas does not come into contact with the copper / copper alloy. Thereby, with respect to copper or copper alloy which is easily corroded (that is, oxidized), the corrosion resistance is improved and consideration is given so that patina or the like is not generated by gas (especially water vapor). Due to the thermal conductivity of copper or copper alloy and the corrosion resistance of nickel, it is suitable for the specific use of the cold trap 10 (freezing and collecting water molecules).

Furthermore, the inner side surface of the cold panel 200 (the trap surface facing the inner side of the vacuum chamber) may be configured to be formed into a ground shape by, for example, blasting or peening, so as to increase the surface area. In addition, it is good also as an uneven surface in which many protrusions were formed, if the surface area could be expanded.
In addition, the outer surface of the cold panel 200 (the surface facing the wall surface side of the vacuum chamber) is configured to have a mirror surface (glossy surface) with as low an emissivity as possible to reduce the emissivity. Thereby, the amount of heat entering from the normal temperature side can be reduced, and the cooling end 105 cold panel 200 can be maintained at a low temperature.

The heater 106 is a specific example of the heating means of the present invention, and is, for example, a heater that is hermetically embedded in the cooling end 105 of the cold panel 200 and is not exposed to the outside as shown in FIG. Configure as follows. This suppresses outgas.
The temperature sensor 107 is a specific example of the temperature measuring means of the present invention, and is disposed so as to be in contact with the surface of the cooling end 105 so that the temperature of the cooling end 105 and the cold panel 200 can be accurately measured.
The seal 111 is an O-ring or the like disposed so as to surround the periphery of the opening 22 of the vacuum chamber 20, and prevents leakage of outside air into the vacuum chamber 20 at the joint between the vacuum chamber 20 and the flange 103.

  A current introduction terminal 112 provided on the flange 103 draws out a current line connected to the heater 106 from the vacuum chamber 20, and a signal lead-out terminal 113 provided on the flange 103 connects a signal line connected to the temperature sensor 107. It is provided for drawing out from the vacuum chamber 20. These terminals 112 and 113 can be used under vacuum, and for example, hermetic terminals are used. Each current line / signal line is covered with, for example, a stainless sheath.

The controller 114 is a specific example of the temperature control means of the present invention, and a current line and a signal line drawn out from the vacuum chamber 20 and a control line from the refrigerator 100 are connected to each other. The controller 114 reads out information as described later with respect to the heater 106 connected via the current line, the refrigerator 100 connected via the control line, and the temperature sensor 107 connected via the signal line, Perform various controls.
The power source 115 supplies power to the heater 106 and the refrigerator 100 via the controller 114. The cold trap 10 is configured in this way.

  Subsequently, an operation when the vacuum exhaust apparatus 100 is operated will be described. In the vacuum exhaust apparatus 1000 shown in FIG. 1, the turbo molecular pump 30 is operated to exhaust from the vacuum chamber 10. At this time, the cold trap 10 is operated to collect water vapor in the vacuum chamber 20, and turbo molecules are collected. This prevents water vapor from reaching the pump 30.

  When the gas in the vacuum chamber 20 starts to be exhausted due to operation, the pressure of the gas in the vacuum chamber 20 starts to decrease. As the pressure of the gas in the vacuum chamber 20 decreases, the water in the vacuum chamber 20 vaporizes into water vapor.

In the cold trap 10, as shown in FIG. 2, the controller 114 starts the operation of the refrigerator 100 and feeds back the temperature measurement signal output from the temperature sensor 107, thereby maintaining the cold panel 200 at a predetermined temperature. .
For example, as an example of the predetermined temperature of the cold panel 200, a temperature within a range of 120K to 150K (−153 ° C. to −123 ° C.), which is an optimum temperature for freezing and collecting only water vapor, is selected and controlled. Water vapor is frozen and collected.
Thereby, moisture in the vacuum chamber 20 is adsorbed, and molecules other than moisture are compressed by the turbo molecular pump 30 to a high compression ratio and exhausted.

Such a cold trap 10 has the following advantages.
In particular, in the prior art, the cold panel 200 could not exceed the pipe or casing diameter, but in the present invention, since the cold panel 200 is arranged in the vacuum chamber 20 having a large volume, the cold panel 200 can be enlarged. And increase the collection ability.
Furthermore, since it is not located in the piping, the exhaust conductance is lowered and the exhaust capacity is also increased.
These effects combine to achieve low power consumption.

  Further, in the prior art GM type refrigerator, once operated, it was continuously operated at the rated regardless of the load. However, in the cold trap 10 of this embodiment, the operation of the pulse tube type refrigerator 100 is It is only necessary to set the power to an optimum temperature according to the adsorption capacity of the cold panel 200, and wasteful power consumption can be avoided.

The cold trap 10 can be directly cooled and heated on the cold panel 200 by using the refrigerator 100 for cooling, using the heater 106 for heating, or using the refrigerator 100 and the heater 106 together. Both are possible, and can be controlled to an arbitrary temperature in a wide range of 60 K to 573 K (−213 ° C. to 300 ° C.), and select not only water vapor but also any gas (for example, Br ₂ , NH ₃ , Cl ₂ , CO _2, etc.) It is also possible to adsorb.

  Next, another embodiment of the cold trap will be described with reference to the drawings. FIG. 4 is a configuration diagram of another form of cold trap. The cold trap 11 of the present embodiment has almost the same configuration as the cold trap 10 previously shown in FIG. 2, but in this cold trap 11, the opening area of the opening 22 of the vacuum chamber 20 is particularly increased, and the cold panel 200. Can also pass through the opening 22. In addition, the area of the flange 103 was increased in correspondence with the increase in the opening area of the opening 22. Thereby, if the flange 103 is removed from the vacuum chamber 20, the entire cold trap 11 can be removed from the vacuum chamber 20, so that disassembly during assembly and maintenance is facilitated.

In the above, each form was demonstrated. In the cold traps 10 and 11 of the present invention, since the cold panel 200 is disposed in the vacuum chamber 20, it is possible to enlarge the cold panel 200 by removing the restrictions on the design of the cold panel 200, and to freeze and collect water molecules. Increase the adsorption capacity by increasing the surface area of the trap surface of the cold panel. Further, since the mechanical support is provided by the high thermal resistance stay 203 and the thermal insulation collar 204, the surface area of the trap surface of the cold panel 200 is also increased in this respect, thereby realizing an increase in adsorption capacity.
Further, since the cold panel 200 is not disposed in the gas flow path of the pipe 40, the exhaust conductance can be greatly reduced and high-speed exhaust can be realized.

Furthermore, in the refrigerator 100, the regenerator and the pulse tube, which are the components of the expander 104, are configured by thin pipes. For this reason, it is not preferable to apply a large load to the cooling end 105. However, the cooling end 105 of the expander 104 and the high thermal resistance stay 203 have a difference in thermal expansion in the axial direction of the high thermal resistance stay 203. Therefore, when the cold panel 200 is mechanically firmly fixed, the cooling end 105 Excessive force may be generated. Moreover, the possibility of the expander 104 being damaged by external vibration such as an earthquake could not be denied.
Therefore, since the structure in which the flexible heat conducting member 109 is interposed as in this embodiment is adopted, the cooling end 105 becomes independent from the influence of the mechanical deformation due to the difference in thermal expansion and vibration as described above, and has a high thermal resistance. The stay 203 and the thermal insulation collar 204 may provide mechanical support of the cold panel 200 firmly, increasing the degree of freedom in mechanical design, and finally realizing an increase in adsorption capacity and high-speed exhaust.
Combined with these effects of increasing the adsorption capacity and greatly reducing the exhaust conductance, significant low power consumption can be realized.

1 is a block configuration diagram of an evacuation apparatus including a cold trap according to the best mode for carrying out the present invention. It is a block diagram of a cold trap. It is a structural diagram of a high thermal resistance stay. It is a block diagram of the cold trap of another form. It is explanatory drawing of the vacuum exhaust apparatus of a prior art. It is explanatory drawing of the vacuum exhaust apparatus of a prior art.

Explanation of symbols

1000: vacuum exhaust device 10, 11: cold trap 100: refrigerator 101: compressor 102: radiator 103: flange 104: expander 105: cooling end 106: heater 107: temperature sensor 108: heat conduction member 109: flexible Heat conductive member 110: heat conductive member 111: seal 112: current introduction terminal 113: signal derivation terminal 114: controller 115: power supply 200: cold panel 201: flat circular panel 202: hat-shaped panel 203: high heat resistance stay 203a: titanium Alloy pipe 203b: Through hole 203c: Screw part 203d: Screw part 204: Thermal insulation collar 20: Vacuum chamber 21: Internal device 30: Turbo molecular pump 40: Piping

Claims (14)

A refrigerator having a compressor, an expander and a cooling end;
A flexible heat conducting member thermally connected to the cooling end;
A cold panel thermally connected to the flexible heat conducting member;
A high thermal resistance stay that is formed of a member having high thermal resistance and supports the cold panel;
A refrigerator in which a refrigerator is disposed on one surface, and a high heat resistance stay, an expander, a cooling end, a flexible heat conducting member, and a cold panel are disposed on the other surface;
A vacuum chamber having an opening;
With
A cold trap characterized in that a cold panel is arranged in an internal space of a vacuum chamber by closing an opening with a flange. The cold trap according to claim 1, wherein
The high thermal resistance stay is
A titanium alloy pipe having a hollow portion and a through hole communicating with the hollow portion;
A fixing portion fixed to both sides of the titanium alloy pipe and attached to the flange and the cold panel;
A cold trap characterized by comprising: In the cold trap according to claim 1 or 2,
The cold trap, wherein the flexible heat conducting member is an oxygen-free copper mesh wire. In the cold trap as described in any one of Claims 1-3,
A thermal insulation collar that mechanically connects the high thermal resistance stay and the cold panel and suppresses heat conduction;
A cold trap comprising: In the cold trap as described in any one of Claims 1-4,
The cold trap is composed of a flat panel made of a flat plate and a hat-shaped panel having a convex portion, and is formed by attaching a hat-shaped panel while bringing the convex portion into contact with the flat panel. In the cold trap as described in any one of Claims 1-5,
The cold trap according to claim 1, wherein the expander is a pulse tube expander. In the cold trap as described in any one of Claims 1-6,
The cold panel is made of pure titanium having a high thermal conductivity in a low temperature region. In the cold trap as described in any one of Claims 1-6,
The cold panel is made of copper or a copper alloy having a high thermal conductivity in a low temperature region. The cold trap according to claim 8,
The cold trap is characterized in that a protective layer for improving corrosion resistance is formed on the surface of the cold panel. In the cold trap according to any one of claims 1 to 9,
A heating means connected to a current line via a current introduction terminal provided on the flange and heating the cold panel;
A temperature measuring means for measuring the temperature of the cold panel, connected to the signal line via a signal derivation terminal provided on the flange;
A heating means via a current line, a refrigerator via a control line, a temperature measurement means via a signal line, and a temperature control means connected respectively.
With
The temperature control means controls the refrigerator or the heating means so that the temperature of the cold panel is set to a predetermined temperature based on the temperature of the cold panel measured by the temperature measurement means. The cold trap of claim 10,
The heating means is arranged so as to be built in the cooling end,
The cold trap is characterized in that the temperature measuring means is arranged so as to be built in or in contact with the cooling end. In the cold trap as described in any one of Claims 1-11,
The vacuum chamber includes an opening formed by an opening area through which at least a high thermal resistance stay, an expander, and a cooling end pass,
After passing the high thermal resistance stay, the expander and the cooling end through the opening of the vacuum chamber and closing the opening with a flange, the cooling end and the cold panel are thermally connected by a flexible heat conducting member, and the high thermal resistance stay A cold trap, wherein the cold panel is formed integrally with the vacuum chamber by connecting the cold panel and the cold panel. In the cold trap as described in any one of Claims 1-11,
The vacuum chamber includes an opening formed in the vacuum chamber with an opening area through which at least a high thermal resistance stay, an expander, a cooling end, a flexible heat conducting member, and a cold panel pass,
A refrigerator is arranged on one side, and the opening is closed by a flange on which a high heat resistance stay, an expander, a cooling end, and a cold panel are arranged on the other side, and a vacuum chamber By passing the high thermal resistance stay, expander, cooling end and cold panel through the opening of the hood and closing the opening with a flange, the cold panel is arranged in the interior space of the vacuum chamber and is formed integrally with the vacuum chamber A cold trap characterized by The cold trap according to any one of claims 1 to 13,
A turbo molecular pump that exhausts gas in a vacuum chamber formed integrally with the cold trap;
An evacuation apparatus comprising:

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